Gold Lion KT88's Upgrade

Yes, get them from Jim McShane over on Audio Asylum. I think they are a great tube.

Ensure they are a matched Quad.

How about a matched quad of Penta Labs KT-88SC tubes from Doug's tubes in place of the Gold Lion KT88's?

I don't know about KT-88's........but......I replaced the stock Svetlana EL-34's in my Rogue Audio Cronus with Gold Lion KT-77's, and the musicical improvement is sublime.

I've tried KT88s, 6550s, and KT120s in my new Jolida. The KT120s won the spot (spots) in my amp. They're only made by one company though, so the only options for 'em is to buy "cryoed" or not. I went with non cryoed and they really kick ass, and I've noticed a lot of respected tube amp companies are using 120s now. They're not expensive so I figured it was worth trying 'em. I bet New Sensor will roll out some supposed "Premium" version with gold pins and upscale gold printed glass...maybe a "presentation" padded box. If they don't they're missing a sure bet.